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The subject of retarding a moving vehicle or object in a controlled manner has been investigated over hundreds of years with many different solutions being developed over the years. As time has progressed a common overall design has almost uniformly been agreed upon for vehicle use; a brake disc and caliper or brake drum arrangement. As vehicle refinement has improved there has been increasing focus on the refinement of such designs with regards to their noise, vibration and harshness (NVH)characteristics. Whilst brake noise has had significant research analysing its cause, effect and solutions, brake judder has had less research focussed upon it. The principal reason for past research priorities and the recent interest in judder is because of the increased demands being placed on brakes – higher power absorption with lighter structures. The subject of this thesis was to address the least known phenomena of brake judder, that of the thermo-elastic deformation of vented brake discs. The research utilised experimental, analytical and empirical methods to give a broader understanding of the transient deformation process, both thermo-plastic and thermo-elastic, of a high performance vehicle disc brake. Initial characterisation of thermal judder was carried out on-vehicle where it was identified that brake pressure could be used as a reliable indicator to show the developing nature of this phenomenon. The brake pressure pulsation was shown to change from low order (first or second order) to high order (up to eighth order) over the duration of a high speed vehicle brake test which involved up to thirty braking events. The pressure pulsation indicated a link to brake disc deformation with the magnitude and order of brake pressure variation increasing with increasing disc temperature. The highly dynamic, transient, nature of brake disc distortion was also investigated on a bespoke quarter car suspension brake dynamometer. Thermoelastic wave-like deformation was shown to occur during the process of a single braking event with the order of deformation corresponding to the brake pressure variation. The order of this wave-like deformation was shown to be linked to the amount of energy transferred into the braking system with higher energy braking events resulting in higher order deformation. Thermal images of the brake disc have shown an equispaced formation of hot-spots on the inboard and outboard friction ring surfaces which was linked to the disc waveform. The wave-like deformation was attributed to circumferential buckling of the brake disc as suggested by Lang [1]. This resulted from rapid thermal expansion of the friction rings due to the sudden - 4 - influx of heat during braking. Thermal gradients between the hot and cold regions of the brake disc constrained the radial thermal expansion of the friction ring and caused compressive stresses to build up. When the tangential load causing the stress was in excess of the critical buckling load, buckling of the brake disc occurred with the mode order of the buckled disc related to the temperature of the friction ring. Stress relieving of the brake disc was shown to occur during brake testing on the brake dynamometer causing a thermo-plastic effect. This “in service” stress relieving effect removed the retained stresses resulting from the casting and machining processes and allowed the disc to adopt a second order mode of deformation. Data from the on-vehicle and dynamometer testing was used to generate and validate finite element analysis simulations which were used to investigate thermal inputs and heat dissipation from the brake disc. These findings were then combined with that of an associated aerodynamic study [2] to generate a modified brake disc vent profile which reduced the surface temperature variation, thermal gradients and maximum disc temperature. On-vehicle testing of the prototype design showed an average 14% reduction in maximum disc temperature and it was proposed that this would reduce the propensity for the disc to generate judder by reducing the thermal deformation of the brake disc.

The aim of this research was to determine the relative importance of glutathione S-transferase (GST) mediated herbicide and fungicide detoxification in wheat plants and to functionally characterise GSTs cloned from phytopathogenic fungi. Wheat seedlings treated with and without safeners were used for in vivo and in vitro pesticide metabolism studies with the herbicide fenoxaprop-P-ethyl and the fungicide fluquinconazole, which are both known to undergo glutathione conjugation. Fenoxaprop-P-ethyl underwent rapid detoxification by this route and the rates of metabolism were enhanced in safener treated wheat. In contrast, fluquinconazole was poorly metabolised with only a small proportion detoxified by glutathlonylation irrespective of whether or not the plants were safener treated. Subsequent studies confirmed that whereas fenoxaprop was a substrate for wheat GSTs, fluquinconazole was not. Similarly, when a diverse range of systemic and contact fungicides was tested, none were found to undergo conjugation mediated by wheat GSTs, even though several compounds underwent conjugation with glutathione in alkaline conditions. Metabolite profiling by HPLC-MS established that the alternative thiol present in wheat, hydroxymethyl glutathione, was used in addition to glutathione in fenoxaprop detoxification. The S-conjugates were then further metabolised by peptidases and glucosyl- and malonyl transferases to yield polar derivatives such as the cysteinyl-malonyl-glucosyl derivative. This rapid processing was in contrast to that determined in herbicide-susceptible and herbicide-resistant black-grass, where the glutathione derivative was the major metabolite of fenoxaprop. Using an informatics approach, GSTs in IVIagnaporthe griseae and Phytoptithora infestans were identified cloned and then expressed in E. coli, with the pure enzymes assayed for glutathione-dependent activities. MgGSTX1 of Magnaporthe griseae was found to be a member of a novel class of GSTs (termed xi class) and was shown to function as a thioltransferase, with a specific activity of 50.4 ± 3.4 nKat mg (^-1)protein. Unusually, the catalytic mechanism of thiol transfer was insensitive to the alkylating agent iodoacetamide, indicating that free cysteines were not involved in catalysis. MgGSTX1 did not conjugate any of the experimental xenobiotics tested with GSH. The theta class GST P/GSTT1 cloned from P. infestans exhibited glutathione peroxidase activity and readily detoxified fungitoxic oxylipins produced by potato as antimicrobial defence by potato through the action of lipoxygenases. Using anti-sera raised against the purified recombinant protein, immunoblotting experiments revealed expression of P/GSTT1 in the in vitro cultured fungus as well as during colonisation of potato. P/GSTT1 did not demonstrate GSH conjugating toward any of the xenobiotic substrates tested including herbicides and fungicides. Based on the sequences of GSTs identified in this study an extension of the existing classification system is suggested to include the GSTs of fungal phytopathogens

The properties of the perfluoropolymer sulphonic acid resin, sold under the trade name of Nafion have been examined. The use of Nafion as a support for transition metal catalysts has been studied in the context of alternative support systems. It has been demonstrated that transition metal complexes are readily incorporated into Nafion, provided they are either ionic in nature or contain ligands which are organic acid anions or ligands which can be protonated. Nafion used as a support has been successfully recycled and forms of Nafion with modified functional groups have been successfully synthesised. In order to explore the scope of Nafion as a catalyst support, a range of reactions has been investigated, the main purpose being comparison between the performance of a catalyst used homogeneously to its performance supported in Nafion. The hydroesterification of ethene to methyl propanoate was studied using several palladium complexes as catalysts. The ejects of temperature, CO pressure, catalyst loading and ligand to metal ratio on yields of product were recorded, using the most effective of the supported palladium catalyst systems. Yields of methyl propanoate using Nafion supported complex as catalyst were higher than the same catalyst used unsupported under comparable conditions. The hydrogenation of cyclohexene, dimethyl maleate and nitrotoluene was accomplished using the complexes [Ir(COD)(PPh(_2)Me)]PF(_6), [Rh(NBD){Fe(C(_5)H(_4)PPr(_2))(_2)}]BF(_4) and [RhCl(Ph(_2)P-NC(_5)H(_10))(_3)]. Yields of hydrogenation products using Nafion supported complexes were comparable or higher than yields obtained homogeneously. The hydrofonnylati n of hexene was carried out using a series of complexes of the form [Rh(NBD)L(_2)]BF(_4) where L represents a phosphine. Yields of aldehydes and normal to branched ratios were slightly lower using Nafion supported complexes in comparison to the homogeneous case. The production of substituted pyridines from propyne and acetonitrile was attempted using cobalt complexes coordinated to modified cyclopentadiene rings without success.

The breeding biology of the House Martin Delichon urblca (L) is described/ with particular reference to the influence of variation in the abundance of aerial insects. The selection of food items from the available resources is explained in terms of a prediction strategy which demonstrates that the Martin consistently maximises the efficiency of food collection,, The timing of the breeding season and breeding success are respectively shown to be closely associated with the development of the aerial phase of several insect populations and with food abundance. A hypothesis is presented, with some supporting evidence, which describes the potential selective forces acting on broods both smaller and larger than the most frequent natural brood sizes which would possibly inflict a disproportionately large mortality on these extreme brood sizes and also on the adults involved in rearing them. This is particularly relevant: to those species where artificially enlarged broods or the largest naturally occurring broods are more productive than the most frequent brood sizes, as is the case in this study. Differences in food and feeding station are described which ensure a degree of ecological isolation between aerial feeding birds in Britain.

The thesis describes the direct measurement of adsorption of electrolytes on some oxide surfaces and electrokinetic measurements made on the same systems. Oxides with the spinel structure were chosen so that variation of lattice constant and chemical properties could be controlled and the extent of their effects on adsorption examined. A number of spinels were prepared from the pure parent oxides or coprecipitated hydroxides. The surface areas of some samples of the spinels, prepared for adsorption studies, have been measured by a B.E.T. isotherm method. Propane was used as the adsorbate gas, conveniently giving pressures of the order of 10 cm at solid carbon dioxide temperatures. The eleotrokinetic behaviour of two of the spinels, MgA1204 and NiAl204, was studied by the streaming current technique. Methods of analysing small quantities of solutions of divalent metal electrolytes at low concentration were devised so that the adsorption of these electrolytes could be determined. The results are less satisfactory than expected; in a number of cases the total cation and anion concentrations did not agree, indicating at least a partial failure of the analytical technique.

The main purpose of this thesis is to investigate the dynamic centre of pressure during a noisy brake application. A novel technique is employed to measure the centre of pressure and contact pressure distribution between the disc/pad interfaces during braking events. The test rig was developed to study the contact pressure distribution between disc/pad interfaces. The caliper and set of pads were modified to measure both static and dynamic centre of pressure during braking events. The brake uses a 12 piston opposed caliper arranged to allow a number of the pistons to be controlled independently using 4 master cylinders. This allows the interface centre of pressure to be adjusted both along the length of the pad and radially. The tests included static pressure measurements with the sensor film between the pad friction face and the disc, the centre of pressure being adjusted using the master cylinders to provide a “system benchmark”. Once the static characteristic behaviour of the modified pad is established, the centre of pressure variation is measured under dynamic conditions. This allows the movement of the centre of pressure to be plotted against brake pressure and rotor speed. Furthermore, a detailed finite element model of a disc brake assembly is developed. Contact analysis was performed to determine the pressure distribution, interfacial contact area and normal contact forces under both frictionless (μ=0) and frictional braking conditions. The effect of varying friction coefficients and the brake hydraulic pressure is also examined. Preliminary finite element results of contact pressure distribution between the disc/pad interfaces were compared with the experimental results, followed by a detailed modal analysis of disc brake to predict the natural frequencies and the mode shapes of disc brake. In addition, a stability analysis of brake assembly is carried out to distinguish the unstable frequencies. Structure modification of disc brake assembly was also investigated to understand the characteristics behaviour of brake system in terms of squeal noise performance. It is established from the results that there is a strong relationship between the interface pressure distribution, the effective centre of pressure and the propensity of the brake to generate noise. It is noticed that the centre of pressure may vary both along the pad and radially during braking which adds to the complex analysis of instability. The finite element results compared well with the experimental results. It is observed that the contact pressure distribution and the magnitude of normal contact forces are much higher towards the leading edge of the pads comparing to the trailing edge. It is also established yet again that with a leading centre of pressure the brake is more prone to noise whereas with a trailing centre of pressure the system is more likely to be stable.

Disturbance from engineering works is an increasing problem in terrestrial and marine ecosystems throughout the world. Many reported declines in population size, breeding success and body condition have been diagnosed as the result of anthropogenic disturbance, however little is known about the effect of long-term disturbance from large-scale engineering works. Understanding the mechanisms by which animals respond to anthropogenic activities is fundamental to explaining interactions, and resolving potential conflicts between humans and wildlife. This thesis focuses on the factors affecting the habitat use and foraging decisions in wintering shorebirds and wildfowl. The first half of this thesis considers the direct and indirect impacts on waterbirds of a major engineering project in central Scotland; construction of the new Clackmannanshire Bridge at Kincardine-on-Forth. For individual bird species in close proximity to the bridge site, round-the-clock construction work had consequences ranging from neutral to considerably negative. Cormorant Phalacrocorax carbo declined in the area, probably as a result of the disturbance of an important low tide roost. Redshank Tringa totanus, previously abundant in the prey-rich areas adjacent to the construction site, were displaced into poorer areas for most of the construction period; where they may also have suffered from increased interference competition and elevated risk from raptorial predators. Some positive effects of industrial development were also revealed; radio-transmitters combined with tilt-switch posture sensors indicate that Redshank were able to capitalise on the improved nocturnal visibility in areas around Grangemouth docks to assist with foraging and predator detection. Evidence is presented that birds switched foraging strategy (from sight to touch feeding) depending on ambient light levels; whereby artificial light was used in a similar manner to moonlight to assist with prey detection. Redshank also avoided riverine areas at night that were used frequently by day, probably in response to an elevated threat from nocturnal predators. As the predator landscape changes from day into night, birds adopt different strategies to minimise the risk from nocturnal predators. It is clearly important, therefore, that information on nocturnal distributions is available to inform decisions on site management, especially where anthropogenic activity continues throughout the diel cycle. Behavioural decisions were shown to vary widely within a species depending on individual state, metabolic demands and previous exposure to human disturbance. Prey resources were shown to change dramatically over the course of a winter. In response to this decline, the home range of Redshank contracted over a winter season. Similarly, animals responded less and took greater risks in response to experimental disturbance events later in the winter than earlier in the winter, and on days when the temperature was lower. This effect was strongest for individuals occupying heavily disturbed areas, which were possibly already compensating for lost feeding time and a negative energy balance. The results were consistent with the hypothesis that those individuals that respond most obviously to human disturbance were those least likely to suffer fitness consequences. This is the opposite from what is commonly assumed when behaviour is used as an index of disturbance impacts, most notably in the use of flush distance in the design of wildlife buffer zones. In conclusion, this study demonstrated various negative impacts of disturbance, including local displacement, due to construction activity on overwintering waterbirds. It also revealed two key, but poorly understood, phenomena relating to mechanisms for coping with anthropogenic disturbance: routine utilisation of artificial light to extend night-time feeding opportunities amongst Redshank and an adaptive flexibility in escape responses across a range of species under varying conditions of risk.

Conservation of intertidal habitats in the UK is vital in order to continue to support nationally and internationally important populations of non-breeding waterbirds. Historic reclamation for agriculture and industry has resulted in the loss and degradation of large areas of these intertidal habitats in estuaries and they continue to be threatened by sea-level rise. Managed realignment is one method which is increasingly being used to restore intertidal habitats. As managed realignment is a relatively new restoration technique, the extent to which knowledge of the biology of estuaries is applicable to managed realignment sites is unclear. Habitat restoration is often unsuccessful or incomplete, so a detailed knowledge of both the natural system and the characteristics of restored systems will usually be necessary to recreate fully-functional estuarine habitats. This thesis focuses on Nigg Bay Managed Realignment Site (Nigg Bay MRS), the first managed realignment site in Scotland, and follows the first four years of ecological development to gain an understanding of how breached realignment can be used to restore intertidal habitats to support non-breeding waterbirds. This thesis has six major aims: (i) to describe the development of saltmarsh, (ii) to describe the development of intertidal flat, (iii) to describe the colonisation by non-breeding waterbirds (iv) to determine how tidal cycle and weather affect patterns of waterbird use, (v) to determine which factors affect the spatial distribution of waders and finally (vi) to determine the patterns of use by individual birds. Four summers after the re-establishment of tidal conditions, almost all of the saltmarsh species recorded on the nearby saltmarsh had colonised Nigg Bay MRS, although recognisable communities had yet to establish. Three winters after the re- establishment of tidal conditions in Nigg Bay MRS, the sediments had a significantly smaller particle size and higher organic matter content compared to the fine sands of the adjacent intertidal flats. The intertidal invertebrate community also differed from the adjacent intertidal flats. Nigg Bay MRS attracted large numbers of non-breeding waterbirds and supported each of the most common wader and wildfowl species present in the wider estuary. Nigg Bay MRS performs a number of important functions for non-breeding waterbirds by: (i) providing a foraging and resting habitat when the tide is absent and intertidal sediments in Nigg Bay are exposed; (ii) providing a foraging resource as the tide passes over the intertidal sediments within the site once the intertidal flats in Nigg Bay are inundated; and (iii) providing a high tide roosting site. On days with low temperatures and high wind speeds, more waterbirds use Nigg Bay MRS, suggesting that it is likely to be providing sheltering benefits. Nigg Bay MRS also provides top-up feeding habitat. The factors that often influence the spatial distributions of waders in estuaries appear to be operating within Nigg Bay MRS. Wader densities are greater on the intertidal flats when they are accessible than on the saltmarsh. Wader densities are also greatest close to creeks and drainage channels, possibly due to higher invertebrate densities, more accessible prey or sheltering benefits. Colour-ringing and radio-tracking of Common Redshank established that Nigg Bay MRS has a subset of regular users, including both adults and juveniles, and the wader assemblage at night may differ from the assemblage during the day. These findings are discussed in terms of the implications for locating, designing and managing future managed realignment projects.